The study explored lifetime prevalence of non-suicidal self-injury (NSSI) in female and male individuals with eating disorders (ED) and compared ED symptoms, general psychopathology and personality traits across individuals with and without a history of NSSI. The incremental discriminative capacity of gender on the manifestation of lifetime NSSI was also studied. A total sample of 1649 consecutively admitted ED patients (1515 women and 134 men) participated in the current study [339 ED + NSSI (ED with NSSI) and 1310 ED - NSSI (ED without NSSI)]. Specific self-report measures were included and other clinical and psychopathological indices. The observed lifetime prevalence of NSSI was 20.6% (20.9% in women and 17.2% in men). NSSI was not associated with ED type or gender. However, ED + NSSI patients exhibited more impulsive behaviour, substance-abuse disorders and additional impulse-control disorders, were younger and had more previous treatments. Age was shown to affect the presentation of NSSI. Additionally, ED + NSSI patients exhibited more severe ED and general psychopathological symptoms and had more dysfunctional personality traits when compared with ED - NSSI. ED + NSSI was found to be positively associated with harm avoidance and self-transcendence but negatively with reward dependence, self-directedness and cooperativeness. Thus, the variables with stronger capacity to identify the presence of ED + NSSI were younger age, harm avoidance, self-directedness and self-transcendence. A lack of association between sex and ED subtype with the presence of NSSI was observed.